Frank Lampard has demanded Chelsea players work hard and live healthily following his appointment as head coach, though he will not be imposing a ban on tomato ketchup.

After weeks of speculation, Chelsea finally announced the appointment of Lampard on Thursday, signing a three-year deal as Maurizio Sarri's successor.

Lampard spent 13 years at Chelsea as a player and is their record goal-scorer, making him a true Blues icon.

He returns to Stamford Bridge despite having only one season in management, as he guided Derby County to the Championship play-off final last term.

He has spent long enough at the top of football to understand what is expected of players, and although he will not be taking such a hard-line approach that sees him ban tomato sauce, he will see red if members of his squad challenge his methods.

"What we did at Derby, and I will bring here, is that I will have a respect for the players and they should behave like professionals," he told reporters.

"We will lay out everything, and the sports science, nutrition, medical, everything like that is spot on here, I know that from being here.

"So, there are no excuses. To get a top performance, the players have to live right. They have to train hard and rest well, and if they don't it becomes evident.

"I'm a manager who has faith to a point, but if I see it's not being done...

"It's not about ketchup. I'm not banning tomato ketchup. They go home and they can have a whole tub of it, I'll never know that.

"But if I see it [slack performances as a result of an unhealthy diet] showing on the training pitch, I would be strong on that because I think it's important.

"When you're dealing with small differences at the top of the league – and last year there was a gap to the top boys – then you have to try and bridge the gap."